PSI - Issue 22

134 Lígia T. Silva et al. / Procedia Structural Integrity 22 (2019) 130–136 Lígia T. Silva, Bruno Mendes, Carlos Oliveira, Cristina Reis, Paula Silva; José Silva / First International Symposium on Risk and Safety of Complex Structures and Components (2019), Porto, Portugal

The choice of monitoring sites was made with the aid of the PM concentration map for the city of Vila Real. This map was developed by Silva et al. (2016) using a pollutant dispersion model AUSTAL2000 developed by the German National Environmental Protection Agency. This model has been used by several authors to produce horizontal concentration maps of air pollutants (Gerharz et al., 2013; Silva, 2015; Paas and Schneider, 2016). The use of a pollutant dispersion model allows evaluating advantageously the way the PM ’ s reach the buildings. Additionally, it is also important to estimate the quantities of particulate matter that hits the buildings and to anticipate the concentration levels present in the atmosphere at different scenarios. For instance, it is possible to study the effect of the wind direction and speed, for specific conditions, such as traffic flow variations and traffic composition. The use of long-term concentration maps (Figure 3) allows making a macro analysis of the built environment of the city and can be used to complement the other data sources. Analyzing Figure 3, it is possible to see the PM 10 concentration that hits the historical buildings façades.

Figure 3. Long-term PM10 concentration map of Vila Real downtown area(Silva et al., 2016).

The particulate matter samples collection was performed by using polytetrafluoroethylene (PTFE) membrane filters with polymethylpentene support ring (2 μm porosity, Ø47 mm ). The samples were evaluated in order to determine the type, chemical composition, morphology and size of the collected particles. In order to obtain chemical and morphological characterization, the following techniques were used in the